line balancing on pitch time

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Every business requires a proper management to make a start, reduce cost pehelp the organization grow profitably. Management wants more output from its wlong as its quality is maintained even if they have to pay a little extra for the additiothat they add to the daily production. But unless the productivity of all employees is in the same ratio, this excess production will only lead to holdups amachines, causing imbalances and build up of production work. It is importanbalancing is maintained and analyzed from time to time believes Paul F. Bowes, Project Director of Performance for Business Productivity Services Ltd., a manconsultancy firm operating in the UK and Asia supporting the apparel industry.

How to Manage Sewing Lines forIncreased Output

Pre-Balancing the LineThe process of correctly defining the specification of the garment is fundamental toefficiency, minimize throughput time and maximize profitability. It is important that this specificinclude a method breakdown showing step-by-step manufacture and include an output pmeasured either by quantity, minutes, or a given cycle time. The initial line balance can beusing a required output or available time.

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Production Line BalancingCase Study Ladies Leisurewear Manufacturer, Sri LankaAs is common with many manufacturing companies in Sri Lanka, this company had supervisornot well trained, and whose main focus was to chase cut work and accessories to make sure team always had work. The balancing problems that occurred got gradually worse, until necessary to work overtime, put extra people on the team, or move work to another team for com

The JAAF team, under my guidance, worked with a model line to improve output through betteOnce we had allocated the manual work of ensuring cut work and trims were available to people (cutting room and stores), we worked with the team supervisor to identify problems.

Once production started, it was evident where the problem was. The visual clues were easy tobalancing problems were evident wherever a sewing operator at a machine was waiting for wora pile of garments was waiting to be sewn on an operation. We asked the sewers who had stand up at their workplace so that we could immediately see what the problem was witoperations. After relayout, we could easily see every machine and their stock of work, so weoperator who had with him more than 10 garments, waiting to inform the supervisor so that ticould be taken.

The supervisor monitored the number of garments with the team and number of garments oevery 30 minutes, to see if the required number of garments were being fed in, processed thtaken off the line.

The supervisors were subsequently trained to do a simple cycle time measurement of a sewiso that she could see how many garments per hour the operator could stitch. If it became cleoperator could not reach the required quantity even after being shown the better method, thenresource was required to be put on the operation to take away any handling, or manual wotrimming. The I.E. department was also tasked with analyzing the operation to see if any wopassed to another operation or eliminated.

Line Balancing Analysis chartsIn the July issue of StitchWorld, there was an interesting article on the meaning of Measure of TI am sure the debate still rages over some of the definitions in the article, one thing that stsomething I have been saying to factories since I started as a Trainee I.E. Cycle timimportant than standard time as it gives an accurate indication of what can be achieved.

Balancing charts can be used for simple balancing or as more detailed tools for analyzing worand eliminating non-value added activities. Case Study 1 Ladies Leisurewear Manufacturer, Sri LankaIn the case discussed above, we trained the team supervisor to carry out cycle times onoperations, and to make decisions on whether to push the operator to achieve the time, add areduce handling, increase the number of operators, or call for I.E. help to change the method.

The I.E. team was trained to use a balancing chart to ensure all operations could be achierequired cycle time, and also for analyzing bottleneck operations.

The bar chart 1 shows variation in work content, with the red line showing the average time peThis was created from taking the cycle times of every operation. The diagram clearly showed operations like 4, 6, 7, 10, 18 and 23 needed additional operators for a better balance to be ach



The bar chart 2 shows the balance achieved with additional operators added. If we notice we soperators being appointed in bottleneck operations 4, 6, 7, 10, etc. while no action wasoperations 5, 9, 11, etc. It was because the trimming was added to these operations to balanfrom another operation.

The production output from the 32-operator team averaged 92 pieces per hour, even after basome of the above operations with additional operators; the average output was at 110 pieces p

The I.E. department with the JAAF team tackled all those operations above the red line (averaoperation), and those operations with little work content.

Operation 1 and 3 join together Operation 8 removed trimming anoperation 9

Operation 10 removed trimming and added tooperation 11

Operation 12 and 16 join together

Operation 14 and 15 join together Operation 17 improved the handliOperation 19 add an operator Operation 21 add an operator

The result of the changes (shown in the balancing bar chart 3) was decrease in number of ope32 to 31 and an increase in output to 115 pieces per hour; an increase in productivity of 29%output per operator. The balance was still not ideal, but was improved and could be improved more study.



Case Study 2 Contourline, Sri LankaContourline makes sportswear products and is a great example of implementing leanmanufacturing practices. The management team, under a strong leadership, has driven major flow and pull of work.

One of their major achievements was to set up a sewing team working to a takt time on all operbalancing chart was used to analyse the details of each operation (bar chart 4) to ensureoperation could be achieved in less than the takt time required.

Thread breaks, bobbin changes, and other occasionally occurring elements were added to the



and 5-10% extra time per operation was added for variations in material, speed, hanunforeseeable interruptions.

The detail of the balancing chart makes it easy to see which operations need to be checkejoined, and also where the attention needs to be applied on the pick up and alignmemachining, or check, trim and placing work aside.

The operations are performed in linear sequence, i.e. operation 4 is performed after operation 315 is performed after operation 14, and so on

Operation 4 was allocated the trimming from operation 3. The trimming was of thread endthe operation, not separation of the garments, for example, the thread ends left after swaistband.Operation 6, 7, 8, 9, 11, 12, 14, 18, 19 an operator was added.Operation 15 was allocated the trimming from operation 14.Operation 21 the handling was changed to present the work for operation 22 in a way ththe handling on Operation 22.

The outcome (as shown in bar chart 5) was a sewing team where every operator completed thless than the takt time required, and worked with a single piece flow from operator to operator.was a predictable one piece every 27 seconds (0.45 standard minute takt time) which meant per hour. There was no re-balancing carried out unless an operator could not achieve the takt tim

The takt time (red line in bar chart 5) is the rate of production required to meet the customer sdemand. In this case the customer order was divided by the number of production days availabrequired rate of 1100 pieces per day. The takt time was calculated by dividing the working hours x 60 minutes) by the required output.

Takt time = (9 x 60)/1100 = 0.49 minutes

Therefore every 0.49 minutes a garment needed to be produced. To give a little bit of security, thwas set at 0.45 minutes, which means the output (with 0 delay time) was 1200 pieces per dafor a loss of 100 pieces per day if any unexpected problems occurred.



ConclusionThe initial balance and continual re-balance of lines is one of the most critical jobs for ensuproduction. It is not an activity that can happen only once and then be ignored for the produnless you are running a one piece flow based on takt time. Every team supervisor must becheck cycle times and assess whether sewing operators are capable of achieving the time required. Decisions can be made quickly using this simple tool.

Balancing charts can be a great tool for analyzing problems and balancing lines, but it takes socollect the cycle times of every operator. Supervisors need to start with monitoring line input vsto see if there is an imbalance, then look for the operations with lots of work. Cycle checking cused to help deal with the bottleneck problems of balancing.

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